


Ill-Conditioned

by Bitenomnom



Series: Mathematical Proof [6]
Category: Sherlock (TV)
Genre: Frottage, M/M, Mathematics, PWP, Somehow this started out as math and ended up as porn
Language: English
Status: Completed
Published: 2012-09-12
Updated: 2012-09-12
Packaged: 2017-11-14 02:17:31
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,074
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/510257
Author URL: https://archiveofourown.org/users/Bitenomnom/pseuds/Bitenomnom
Summary: <blockquote class="userstuff">
              <p>If there was one thing John was always sure to do when Sherlock got in one of his moods, it was to <i>stay away</i>.<br/>Which was precisely why now, amidst a flurry of inspiration to do a little experiment of his own, John was coming down the stairs from his room and preparing to approach the sofa and do whatever else was necessary to get results.</p>
            </blockquote>





	Ill-Conditioned

**Author's Note:**

> Oh god, I don't even know why I am posting this. Or rather, I'm posting this because I need a drabble for today (okay, it's 3:30am, I need a drabble for yesterday, but whatever), and I think that's probably the only reason why. This is a topic from my numerical methods course again; I wanted to do something for operations research because that's the thing I really need to study for, but I couldn't think of anything, so...this happened. It was supposed to be cute and silly but then it was porn and yeah.
> 
> Uhmmmmm, uh, so, I've never written anything this explicit before (not that it's that extensive, or, whatever, but, um), so I'm sorry if it's really bad. Apparently this week is Porn 101 for me since a few days ago I also drew my first pornographic drawing. @_@ ([Also Johnlock, not related to this story.](http://toasterfish.tumblr.com/post/31186116380/guys-i-dont-even-know-ive-never-drawn-porn)) Pretty sure this qualifies as PWP? I mean, it's so short, how much plot could it have, really?  
> Anyway, so, if you like it, um, it'd be super nice to know, and if not...be gentle?

The conditioning of a problem describes how sensitive the output of the problem is to its input. The ratio of the error in the output to the error in the input is called the condition number. If a problem has a large condition number then small perturbations in the input data lead to large changes in the output; the problem is _ill-conditioned._ If a problem has a small condition number, the problem is _well-conditioned._

 

***

 

            John wasn’t above doing an experiment or two—especially when Sherlock was moping about on the sofa, making just enough noise and complaint to prevent John from getting anything productive done. He was much better off staying in one place, as quiet as possible; if Sherlock was suddenly reminded of his presence, he’d request tea or expect John to conjure up a serial killer or he’d insult everything about John from his choice in jumper to his pantry-arranging strategy to the woman he was dating (or had been dating, or would be dating; they were apparently all the same, in Sherlock’s book) to, of all things, the color of his eyes. (“They make no sense, John.” As if he was expected to get them fixed up so they’d make more sense to Sherlock.)

            If there was one thing John was always sure to do when Sherlock got in one of his moods, it was to _stay away._

            Which was precisely why now, amidst a flurry of inspiration to do a little experiment of his own, John was coming down the stairs from his room and preparing to approach the sofa and do whatever else was necessary to get results.

            “Oh, good, you’re up,” Sherlock mumbled. “I’d like some tea.”

            “What, so you can sit there and watch it get cold?” John stopped directly in front of the sofa.

Sherlock, with his limbs draped all about the place, didn’t so much as glance in John’s direction (which was, at this point, mostly _upward_ from where he was and hardly at all to his left, the usual). “You’re making some for yourself anyway and it’s never troubled you before,” he waved John off. It was when John crossed his arms and remained in place that Sherlock finally opened his eyes. “Well? Why are you standing there?”

            “I’m perfectly allowed to stand here. I pay for half this flat and this is the bloody sitting room.”

            This clearly perturbed Sherlock; his lips twisted into a grimace. Was standing in a different place than usual really enough to provoke him?

            Apparently, it wasn’t. Sherlock curled in on himself and turned to face the back of the sofa. “Fine. I didn’t want tea anyway.”

            “Didn’t think so.” John took a seat on the table just in front of the sofa. Perhaps he hadn’t deviated quite enough from his usual course of action yet to get a rise out of Sherlock. He smirked to himself and laid on the table, legs dangling off one end and head supported by his hands weaved behind his back. If he stayed like this too long, his shoulder’d probably start bothering him again—but Sherlock only had to notice it for a moment.

            Notice he did, although he did not turn to face John. “What are you doing?”

            “Oh, just lounging.”

            “You don’t ‘lounge.’”

            “Apparently I do.”

            At this, Sherlock swiftly flipped to lie on his other side and face John, looking him over critically. “That’s not nearly comfortable enough to be considered lounging. You’re just trying to do something stupid in the hopes that it will amuse me, thereby making me less unbearable. If you’re so miserable, John, why are you still here?”

            “You’re right,” said John, and Sherlock’s eyes widened in shock and then narrowed again as John continued, “This isn’t very comfortable at all. Budge up, let me on the sofa.” He stood up from his place on the table.

            Sherlock’s legs shot out from against him to cover the length of the sofa. “I’m using it.”

            “Yes, and I’m sure the sofa appreciates your tossing and turning and kicking it much more than my regular old sitting.”

            “Well, I’m not moving. Now leave me be; go on with your usual dull daily activities.”

            Which, granted, would be doable enough, John thought. But then, he wasn’t done testing Sherlock’s limits; and anyway, Sherlock was still moping on the couch and John still had no hope of getting anything done to his satisfaction while he was, so nothing had been gained—yet. There had to be some sort of a tipping point.

            Sherlock had begun tying the belt of his robe into various interesting knots by the time John’s next idea occurred to him. So Sherlock could recover his bad mood reasonably well from John’s mild intrusion and deviation from the usual—but his tolerance couldn’t be limitless. Sherlock flopped onto his stomach just in time to miss John’s smirk. “I’m actually going to sit on the couch whether you move or not,” John announced. It was a gamble, but…

            “Good luck,” Sherlock mumbled at the pillow into which he had buried his face.

            “Thanks, but I don’t think I’ll need it.” John considered his options—he could sit on some small uncovered region, the back or one of the arms—or he could—well—perturb Sherlock quite directly, which would really be the best for making his point. “It’s easily enough done.” Mind made, John grabbed a discarded periodical from the table he’d been lying on and ungracefully dropped his weight onto the small of Sherlock’s back—that was rather safer than the broader portion, anyway. Legs were a bad option—Sherlock could easily twist around, free himself, and push John off if he sat there.

            “You know, Sherlock,” John ignored both Sherlock’s ‘ _oomph!_ ’ and his subsequent frozenness at John’s positioning, casually flipping through the periodical, “lounging isn’t the only thing I _don’t do_ that I actually consider doing just to get you to stop moping.” He’d been meaning to bring it up—but how does one just _bring up_ to his flatmate that despite one’s almost daily insistence that he’s straight, one keeps accidentally wanking to thoughts of said flatmate instead of that rather fetching woman with the polka-dotted push-up bra one keeps running into (or maybe: who keeps running into _him_ ), at Tesco—or, heaven forbid, one of one’s past girlfriends, especially when one’s flatmate is probably more interested in regional discolorations of centipedes than anything even remotely related to sex?

            “ _Mmph,_ ” said Sherlock into the pillow, and John felt a stroke of guilt.

            “Sorry, I wasn’t trying to pin you here just to tell you that; I can move if…er, right. Well. I was just trying to bother you.”

            Sherlock turned his head to the side so that he was no longer speaking into the pillow. “I _am_ bothered,” he hissed, and John shivered at the sound of it, shifting his weight in preparation to stand up and move a safe distance away; he’d never heard Sherlock so _aggressive_. A hand caught John’s knee firmly enough that he paused.

            “I’m sorry, Sherlock,” John frowned. “I didn’t mean to upset you by blocking you in and attacking you with that, uh, admission, and it’s okay if you’re uncomf—”

            “Keep bothering me,” Sherlock rumbled, and John shivered for a different reason this time. Perhaps something so small as trying to sit on a sofa _could_ have rather unexpected results when a moody Sherlock was taken into a consideration. John licked his lips.

            “Right,” he said. “I think I’m going to need to take up a bit more of the sofa, in that case.”

            “Be my guest.”

            John curled his legs up and leaned over to support his weight on his left arm, letting his legs slide down the length of Sherlock’s own limbs, by and large unclothed beneath the robe. He lowered himself onto Sherlock’s back, biting back a strangled noise as his midsection snuggled tight against Sherlock’s arse.

            “God,” Sherlock let out what sounded like an exasperated groan, “Could you be any _more_ irritating?”

            John stretched forward to mutter into Sherlock’s ear, “Maybe if you ask nicely.” He jerked his hips once, hoping to provide further incentive. He pulled back at Sherlock’s robe and tugged it off with minimal help from Sherlock, lifting away from his body briefly to pull the thing the rest of the way off and throw it on the floor.  
            “Oh, now I’m _cold,_ ” Sherlock snorted, “thanks for _that_.”

            John pulled off his own jumper and undershirt and lowered himself back down to feel the heat of Sherlock’s back against his chest. John reached down to Sherlock’s arse, covered now by only his thin pants, and cupped one of his cheeks. “Are _not,_ ” he said, emphasizing the second word with a squeeze of his hand that drew a choke of surprise from Sherlock.

            “God, John, you’re _heavy_ ,” Sherlock complained, his irate tone not quite convincing, as John laid against Sherlock and pulled his own trousers off. He shuddered at the sudden nearness that accompanied the removal of only a few millimeters’ thickness of fabric, savoring the unexpected intimacy of the entire naked length of his legs held fast against Sherlock’s.

            “Oh, am I?” John answered, and curled his arms up to wrap his hands around Sherlock’s shoulders, harshly shoving his hips against Sherlock’s arse and grunting at the overwhelming heat that accompanied his cock lining up with the cleft through their pants as he thrusted, “Too bad.” Unable to resist the temptation, he thrust again, and again.

            “And _slow_ ,” Sherlock groaned, “you can never keep up with me.”

            John slowed his movements to a torturous pace that he knew he wouldn’t have the willpower to maintain for long, compensating for the decrease in speed with an increase in force, all but grinding his bones into Sherlock.

            “ _Fuck,_ John,” Sherlock gritted half into the pillow. He arched his back to bring his arse closer to John and took advantage of the new space beneath him by stretching one hand down to rest flat against his erection, pressing up on it so that he could brace against it as his hips slid with John’s thrusts. John took it as a cue to hurry his pace, and his thrusting and shoving and rubbing gradually sped up until they became frantic, his feet scrambling for purchase against Sherlock’s legs. As his skin grew hotter and his movements faster, John groaned and crushed his hips down, his groin driving against that perfect dip one, two, three times in deliberate, aggressive jerks before John found the air sucked from his lungs, and all sound with it in the form of a wordless exclamation broken in three places. He held fast to Sherlock as he rode out the rippling aftershocks, realizing with dreamy pleasantness the ejaculate on his belly was also on Sherlock’s back.

            When his mind cleared enough for him to _think_ , he reached beneath Sherlock to his front, wedging his hand between Sherlock’s cock and his hand. “Shall I take care of this?” he muttered into Sherlock’s ear, hoping the quickly cooling stickiness on Sherlock’s back wasn’t enough to pull him away from the moment.

            “ _Mmph_ ,” Sherlock spoke into the pillow again, and John wrapped his hand around Sherlock’s erection and slid it forward with the give of the foreskin, reaching his thumb up to rub at the partially obscured head for a moment, yielding a spasm from Sherlock, and then doing his damnedest to work with the movement’s of Sherlock’s increasingly convulsive jerking and twisting. Sherlock’s throat released sounds in bursts, pressure building and then exploding out in forceful barks as John quickened the movement of his hand. He curled the other hand into Sherlock’s hair and pressed a kiss onto his neck, and then Sherlock was grunting and still, and John’s hand was warm and wet.

            “Look at the mess you’ve made,” Sherlock mumbled, dazed.

            “God,” John rolled his eyes, pulling himself off of Sherlock and rolling off the sofa to stand in front of it once more. “Are you _still_ in a mood?” He crossed his arms. “Watch out, or I may have to resort to more extreme measures.”

            Sherlock smirked and rolled onto his back. “Noted.” He sprawled out as he had been before, though now slightly less clothed and slightly sweatier, slightly stickier, and closed his eyes, affecting his previous imperious tone as he asked, “Now, John, where’s my tea?”


End file.
